1. Field of the Invention
This invention relates generally to a method and a noninvasive device for treating a chest injury and more specifically relates to a method and a noninvasive device for preventing pressure build-up in pleural space (a potential space between parietal and visceral pleuras) of an open pneumothorax (a sucking chest wound), avoiding conversion of a simple pneumothorax into a tension pneumothorax (a magnified version of the simple pneumothorax).
2. General Background
The present invention relates to a method and a noninvasive device for preventing pressure build-up in pleural space of an open pneumothorax, in order to reduce possibility of development of a tension pneumothorax. The open pneumothorax may usually result from an opening on a side in a chest adjacent to a lung caused by a gunshot, knife wound, motor vehicle accident and sometimes fall or other injury accident. The opening caused by the wound creates a path for outside air, body fluids or any combination thereof to flow into thoracic cavity. Since air, body fluids or any combination thereof entering the thoracic cavity through the wound may flow into a pleural space and may not enter the lung, the lung may not be able to inflate properly. Thus, an open chest wall may eventually cause a collapse of the lung on the side of the opening, creating the tension pneumothorax. With movement of air, body fluids or any combination thereof in and out of the open chest wall, some air, body fluids or any combination thereof may be trapped in the pleural space adjacent to the lung on the side of the opening, and the lung and some great veins leading to heart may be compressed. As a result, there may be shortness of breath. In addition, existing atmospheric air, body fluids or any combination thereof in the chest wall may bring contaminants into the chest.
If air, body fluids or any combination thereof enters but does not leave the pleural space, a life-threatening situation may arise. A tension pneumothorax develops as pressure in the pleural space exceeds atmospheric pressure. The physiologic consequences of the tension pneumothorax are similar to a simple pneumothorax, but on a magnified scale. Increasing pressure in the pleural space causes the lung on the side of the wound to collapse. Thus, breathing becomes increasingly difficult and, as a result of a decreasing blood flow into the heart, a number of shocks may occur.
In order to reduce the possibility of the development of the tension pneumothorax, the opening in the chest wall preferably should be normally closed while allowing an outflow of air, body fluids or any combination thereof from the pleural space. Until recently, the opening in the chest wall has been usually treated using Saran (a trademark for identifying a thin plastic sheet) wrap, or using a Vaseline (a registered trademark for identifying a product) gauze covered with sterile gauze, or utilizing an aluminum foil or any other type of occlusive dressing secured with tape so as to seal the wound. However, such methods of treatment may be inefficient if a hole exists in the lung and if the wound is sealed externally since air, body fluids or any combination thereof may enter the pleural space through the hole in the lung and produce a pressure build-up within the pleural space. None of the above listed methods would be capable in such a case to provide an efficient, easy-to-use and easy-to-clean one-way check valve for decreasing the pressure build-up within the body of the patient and for facilitating the outflow of air, body fluids or any combination thereof from the pleural space.
Another recommended method for reducing the possibility of development of tension pneumothorax has been to utilize a valve effect by closing the opening in the chest through the creation of a valve using a dressing while taping only three sides of the dressing, so that any extra air, body fluids or any combination thereof is discharged through the opening. However, the valve effect of the dressing may be neutralized during emergency treatment of the patient, due to location of the wound compared to position of the patient during transportation, due to interference of applied support apparatus with operation of the valve, or due to application of a spine board or of belts or of other emergency equipment.
Depending upon size of the wound, some other methods have been recommended, such as: (a) a condom method comprising taping a condom with an open end and with a closed tip over the wound and cutting off the closed tip of the condom to allow exit of air, body fluids or any combination thereof from the pleural space for smaller wounds, or (b) a glove method comprising using a plastic or rubber glove for covering the wound and cutting off a closed tip of one finger of the glove to allow exit of air, body fluids or any combination thereof from the pleural space for larger wounds. The condom method or the glove method, however, may not be efficient methods since under some circumstances substantial back flow of air, body fluids or any combination thereof into the pleural space may exist, and under other occasions the tip that is cut off may be too small to allow sufficient discharge of air, body fluids or any combination thereof causing pressure build-up in the pleural space.
3. Description of the Prior Art
In the past few years, there have been some improvements in the prior methods of reducing the possibility of development of tension pneumothorax from open pneumothorax by using Vaseline gauzes, plastic wraps, aluminum foils, and other similar wraps. A few patents have been recently registered which explain methods for reducing the possibility of the development of tension pneumothorax. Such patents disclose the use of a one-way check valve to facilitate the expelment of air, body fluids or any combination thereof trapped in the pleural space.
Versaggi et al., U.S. Pat. No. 4,465,062, describes a noninvasive seal for protecting a sucking chest wound using a one-way check valve. The Versaggi valve is located in close proximity to the wound, creating the possibility of interference of fluid from the wound with the operation of the valve. In addition, the seal may have to be removed in case of abundant gathering of fluid in the valve of the Versaggi seal in order to allow removal of the collected fluid from the valve. Each removal of the seal may result in additional collection of air, body fluids or any combination thereof in the pleural space, threatening the patient further. Also, a hollow dome-shaped cap covers the valve, said cap being attached to a bandage base by means of an adhesive located on the upper surface of the base, causing the dome-shaped cap to be fixably attached to the base and delaying any need of removal of collected fluid from the valve.
Clemens et al., U.S. Pat. No. 4,717,382, also describes a noninvasive apparatus for treating a sucking chest wound. Clemens et al. uses adjustable straps to hold the apparatus against the body of the patient and over the wound. Adjustable straps may have several disadvantages in treating the wound. Firstly, variable lengths of strap may be needed to place the apparatus in position on the body of the patient. Secondly, the apparatus may not be in a sufficiently stable and fluid-tight relationship to the wound due to movements of the patient and outflow of air, body fluids or any combination thereof from the pleural space. With medical industry welcoming disposable medical instruments, a final disadvantage of Clemens et al. is the factor that the apparatus is sterilized and reused. Therefore, the application of the apparatus of Clemens et al. may be limited to a certain extent.
Scheremet et al., U.S. Pat. No. 5,160,322, patents an occlusive chest sealing valve used in the emergency closing of an open thoracic wound. Scheremet et al. includes a rigid annular base member (as opposed to a tubular base used in the present invention) permanently secured to a flexible attachment. The tubular base used in the present invention may be more efficient than the annular base member used in Scheremet et al. since the tubular base is not directly attached to the body of the patient. A distance is created between the body of the patient and the tubular base in the present invention, due to the existence of a middle layer and an annular flange between the body and the tubular base, and due to the existence of a bottom part and a middle part of the tubular base between the middle layer and the check valve since the tubular base, rather than the annular base, is being used. In Scheremet et al., the valve and base member are relatively thin and define a top surface disposed in closely spaced relation above the attachment means surrounding the opening of the wound. Also, Scheremet et al. has a dome-shaped housing with spaced cut-out openings on periphery of the housing, such openings forming support struts around the periphery of the housing. In the present invention in contrast, the cover is tubular, with a top surface and a screening means across the top surface, said screening means providing a larger surface area for the exit of air, body fluids or any combination thereof from the pleural space than the surface area provided by Scheremet et al. while protecting the valve from foreign debris and contaminants.
Sova et al., U.S. Pat. No. 5,263,922, protects a valved bandage specifically relating to a device and method for covering an open chest wound. Sova et al. utilizes a self-closing one-way valve section secured over a hole in a sheet used for closing the open chest wound. A disadvantage of Sova et al. lies in attaching the valve to the sheet. Thus, if any clogging results in the valve, the device has to be removed, creating additional flow of air or foreign debris or body fluids or any combinations thereof into the pleural space. In addition, a sufficient amount of pressure from air, body fluids or any combination thereof into the valve is needed in Sova et al. to overcome the resilient force of a spring strip which operates the valve.